Dray overturned by the side of nature trail (5)
I believe the answer is:
trace
'trail' is the definition.
(I know that trace is a kind of the trail)
'dray overturned by the side of nature' is the wordplay.
'dray' becomes 'cart' (I've seen this in another clue).
'overturned' says the letters should be written in reverse.
'by' is a charade indicator (letters next to each other).
'the side of' indicates one should take the final letters.
The final letter of 'nature' is 'e'.
'cart' back-to-front is 'trac'.
'trac'+'e'='TRACE'
(Other definitions for trace that I've seen before include "Track down; tiny amount" , "Copy; describe; draw" , "mark" , "Minute quantity" , "Discover - modicum" .)